This invention relates to a multiple magnification mode copying apparatus, and is particularly concerned with such an apparatus which includes a full and half-rate scanning mirror system. Such a scanning system is commonly used in a xerographic copying machine, and when the machine is a multiple magnification mode machine, the problem arises of how to control the various motions that are needed, firstly to scan the full and half-rate mirrors, and secondly to make the simultaneous adjustments needed to the lens position and relative mirror positions when changing magnification modes.